What is Catapult: Definition and 90 Discussions

A catapult is a ballistic device used to launch a projectile a great distance without the aid of gunpowder or other propellants – particularly various types of ancient and medieval siege engines. A catapult uses the sudden release of stored potential energy to propel its payload. Most convert tension or torsion energy that was more slowly and manually built up within the device before release, via springs, bows, twisted rope, elastic, or any of numerous other materials and mechanisms.
In use since ancient times, the catapult has proven to be one of the most persistently effective mechanisms in warfare. In modern times the term can apply to devices ranging from a simple hand-held implement (also called a "slingshot") to a mechanism for launching aircraft from a ship.
The earliest catapults date to at least the 4th century BC with the advent of the mangonel in ancient China, a type of traction trebuchet and catapult. Early uses were also attributed to Ajatashatru of Magadha in his war against the Licchavis. Greek catapults were invented in the early 4th century BC, being attested by Diodorus Siculus as part of the equipment of a Greek army in 399 BC, and subsequently used at the siege of Motya in 397 BC.

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  1. T

    Getting my Toaster Shooter to shoot higher

    Hi there everyone. I am trying to re-engineer a toaster to shoot out pop tarts really high; like 5-6ft high. I've tried a whole lot of different springs of varying sizes and tension, but nothing really seems to be doing the trick. Can get it to shoot about 2 ft, and that is all. It could be the...
  2. Twellmann

    Energy transfer/loss in catapult

    TL;DR Summary: In a classic catapult the arm usually meets a cross brace that stops it and helps define the exit angle. This seems a bit wasteful. I have been thinking about making a small catapult for my sons class. In a classic catapult the arm usually meets a cross brace that stops it and...
  3. GopherTv

    B What are the energy conservation principles at play in a catapult launch?

    This is the catapult. At equalibrium the spring is 0.09 meters in length. When its fully stretched out its 0.225 meters long and I place a rock (0.205 kg) close to where my finger is on the catapult. The catapult starts with this much energy because 1/2 * k * x^2 90.54 is the spring constant...
  4. GopherTv

    B Calculating the Distance that a Catapult can launch a Projectile

    I know the spring constant of my spring, 90.54 n/m The spring is stretched 13.5 cm Im launching of a deck that is 1.75 meters high
  5. neilparker62

    Strange question — Catapult launching a marble over an obstacle

  6. U

    Catapult spring, Kinetic and Potential energy

    My solutions: When ball is launched horizontally, assuming its velocity is entirely in the horizontal dimension, there is no interaction of the ball with the gravitational field, thus no change in GPE, so all of the EPE (elastic potential energy ) of the spring is transferred to KE of the ball...
  7. DracoMalfoy

    Projectile Motion Kinematics: A catapult launches a rock....

    Homework Statement A catapult launches a rock with an initial velocity of 50m/s at 35 degrees above the horizontal. The rock must clear 3.5m at 10m away in order to make it over a castle wall to get to the enemy. Do the knights succeed? By how much do they clear the wall or miss clearing the...
  8. I

    Calculating the Velocity of a Catapulted Object

    A catapult is pulled back 10cm with a force of 30N. How fast does the stone of mass 0.5kg got at maximum speed assuming no air resistance. I have absolutely no idea how to do this... But, I am assuming you use Ek=1/2mv^2, though I can't figure out how to apply it To rearrange that...
  9. alli66

    Catapult Lab Help: Calculating Projectile Motion and Energy | Physics Lab Tips

    [Note from mentor: This was originally posted in a non-homework forum, therefore it does not use the homework template.] we did a lab on catapult but I'm having trouble figuring out the math? i calculated the hangtime, but all i did was take the original time and divide it by 2, is that right...
  10. J

    Why Does Wire Orientation Affect the Motor Effect in Electromagnets?

    Hii... can someone explain to me why the electromagnetic wire doesn't experience any motor effect when in parallel to the magnetic field of the permanent magnet? And why does a thicker wire increases the catapult effect? Ty in advance :)
  11. Buggsy GC

    How do i calculate the energy lost by my catapult

    I Have built a catapult for a 1st year engineering assignment, I know catapult are extremely energy inefficient and my theoretical catapult calculations prove that, but i don't know how to calculate the exact energy of my projectile as it hits the ground again, I can measure the projectiles real...
  12. Buggsy GC

    How do i find the spring constant for a rope torsion spring

    I have built a torsion wheel catapult (Mangonel) for an assignment,and I need to do some theoretical calculations about the displacement, velocity and time of the projectile, the problem is I don't know how to calculate the spring constant without the displacement of the spring (x) and i don't...
  13. Buggsy GC

    Ideas for a catapult design for an engineering report

    Afternoon every one. I am a first year engineering student in NZ, For my midterm break report I have to design and make a catapult that can meet these specifications. - hit one target within a 0.1 m radius of a target that is 1 m away horizontally from the base of the model catapult. - hit one...
  14. E

    How does a hinged mass affect a catapult's launch time?

    Homework Statement Okay, so I am doing a physics investigation and I am supposed to have a theory I can test. I have a catapult I made myself, and I change the force exerted on the rod of the catapult by changing the mass that hangs by a string. It is a seesaw with a hinged mass on one end. I...
  15. A

    Help with the physics of a Catapult

    So currently i am working on a robot, and i have gone to my physics teacher on how to help me achieve what i want out of it but she was not detailed with her explanation. It is only her second year teaching physics so i don't blame her but this seemed like a good place to put it. So this is for...
  16. D

    Help Design a Catapult to Hit Specific Targets

    Homework Statement For my physics class, I have to design a catapult with specific requirements. The launch angle (in reference to the ground) has to be adjustable, it has to hit specific targets within a range of 3-15 feet (the targets can only be at even distances, so only 4 ft, 6 ft, 14 ft...
  17. K

    Catapult: Rotating Throwing Arm to Reduce Air Resistance?

    Would rotating the throwing arm (2cm by 4cm) to its side reduce air resistance due to the smaller surface area? (Imagine a palm vs karate chop scenario).
  18. A

    Ball Launcher Project for school (hit the target)

    << Mentor Note -- this thread is temporarily being allowed in the technical Engineering forums as long as the OP does the bulk of the work >> Here's the deal, I have to create a device that can launch ball, that bounces into a target that is 5 meters away. The targets are circular, one is 22"...
  19. H

    Could electromagnetism work in a catapult?

    Hi! I am new to the forum and need a little of help in a science experiment I wanted to ask you which of the following catapult systems will be more accurate and efficient: 1. Weight as the source of energy. The weight at the bottom of the beam moves back, the beam will go forward and the...
  20. H

    Looking For Help with Catapult Project

    For my term project we were challenged to build a catapult that can be adjusted to hit 3 pre-determined targets, and 3 surprise targets. I have come up with a design, but I'm not sure it's the most effiecient materials wise. I also would like some insight on the design.I believe I should stop...
  21. G

    Build Pop Can Catapult: 10m High, 15m Far w/ High School Physics

    Hello everyone. Not only that I only have High school physics but I don't even remember most of the physics I learned in high school, so when the idea of creating a pop can (354ml aluminium can) launching catapult that can launch the can at a 10 meter hight and 15 meters far came into my head...
  22. C

    Solving Catapult Project: Finding Spring Constant

    I'm doing a catapult project but I'm sort of confused. I need to find the spring constant in order to get the elastic potential energy. The force of pulling back the catapult lever to 36 degrees above the horizontal is 4.2 N. Right before the lever is at rest, 90 degrees, the force is 1.4 N. One...
  23. P

    What Delta Y Should Be Used to Calculate Viy in a Marshmallow Catapult?

    To calculate the Viy velocity for my marshmallow, what am I supposed to use for delta y? Would it be 0 because my catapult is pulled all the way to ground before I let it go, or would it be the height at which the catapult specifically flings the marshmallow?
  24. J

    Simple Question: What is going to throw farther Catapult or Trebuche

    Hopefully this is the right place to ask this.. if not really sorry In my class I have to design something to throw a simple small piece of wood.. Everyone is trying to build a catapult.. I am not sure what to build.. a trebuchet or a catapult and what specific design is going to give me the...
  25. A

    Designing a far flying catapult launched model glider

    Many of you are familiar with the catapult launched profile fuselage gliders that are sold in hobby stores. Since these tend to rather fragile, I am designing gliders with better durability out of card, and also with a full fuselage. These will have a 20 cm wingspan typically. Given that low...
  26. C

    Instantaneous velocity and a catapult

    Homework Statement A stone of mass 5 g is projected with a rubber catapult. If the catapult is streched through a distance of 7 cm by an average force of 70 N, calculate the instantaneous velocity of the stone when released. Homework Equations work done in elastic material w = 1/2 fe =...
  27. C

    Catapult Trigger: Creative Ideas for Pulling String

    Does anyone have any cool ideas for a catapult trigger. I plan to have a hook attached to bottom of cup that holds the ball and 2 hooks on the base that when you pull the catapult all the way down and put a nail through all three hooks. There will be a string attached to the nail but I need...
  28. C

    Enhancing a Catapult Project: Ideas for Angle Adjustment and Trigger Mechanism

    I'm making a catapult in physics. Does anybody have any ideas of something I can install to the catapult to allow me to change the angle of the catapult to any given angle. Also for the trigger mechanism for the catapult what is something cool I could do? I was thinking something to do with...
  29. C

    Maximizing Projectile Range on a Class 1 Lever Catapult: Tips & Tricks

    I have here a class 1 lever style catapult built using leaf springs (A Da Vinci design) which relies on the stored energy in the springs to apply torque over a certain distance which is the length of the arm. Of course, for max distance the arm will stop at 45 degrees or pi/4 RAD. Now here is my...
  30. K

    Calculating Catapult Velocity: Grade 12 Physics Guide

    For grade 12 physics we have built a catapult and it is now our job to determine a few things about it. Its a fixed arm rotating around a lever. It's energy comes from a band stretched when the catapult is wound back. (band is attached to base and onto non-throwing portion of arm) I am just...
  31. dbmorpher

    Catapult MA: Wheel & Axle, Lever, Crank?

    Our class was tasked with building a catapult. We built ours based on DaVinci's We have a wheel and axle MA of 8 and a lever MA of 0.108 We used a crank to stretch the cords, is this a machine that should be calculated in?
  32. D

    Need help with force of spring needed to launch mass from catapult

    Hi All I need help with a physics calculation. I have a mass of 3kg that has to be launched for Earth (9.81m/s^2 gravitational acceleration) at an angle of 30 degrees from horizontal from a catapult. The distance the mass can travel in the catapult is 2m. What I need to know is what is...
  33. B

    Maximizing Projectile Distance with Torsion Spring Catapult

    Homework Statement Determine maximum distance an one ounce projectile can be launched with a torsion spring catapult. Homework Equations E = F * d = 1/2 * m * v02Note: Theta is the measurement of how far the lever arm is being pulled back. Am I missing something?
  34. D

    Catapult Lab could someone assist me?

    Homework Statement http://i.minus.com/i725WMEqetlYA.jpg Homework Equations y=Voy * t + 1/2(9.8)t^2 VFy^2=Voy^2 + 2gy Vox=Magnitude(Cos(Angle)) Voy=Magnitude(Sin(Angle)) The Attempt at a Solution No clue
  35. A

    Catapult project junior year high school

    Hi, I have to do a high school project in physics regarding to build a catapult. The catapult must launch a tennis ball 12 meters from the launch line into the trash can. My friends and I are confused on what materials to use in this project and how to exactly make it so it can fit the...
  36. J

    Calculating the Speed of an Object Launched by a Spring Catapult

    A spring catapult consists of a massless spring and a massless cup. An object of a certain mass is loaded into the cup, the spring is extended to a length L, and the object is launched horizontally. What is the speed of the object? s is the natural length of the spring, L is the length...
  37. A

    How can I increase the distance of a catapult launch with a hollow ball?

    I'm building a catapult meant to fire a plastic ball as far as possible with the following items: 36 popsicle sticks, glue, 6 rubber bands, 4 clothes pins, a small stryofoam cup, and 4 feet of string. The ball has a radius of just under an inch, and it is very light. I am not meant to modify...
  38. C

    Help with catapult calculations

    hi so i had to build a catapult and it's very small, but i need to find the total velocity of the ball upon impact and the maximum height reached. You might need to explain a little bit because I tend to not get things when they are vague so please post more than a formula. Please and thank you...
  39. M

    Optimizing Your Catapult: How to Calibrate for Maximum Distance and Accuracy?

    My current physics project is to design a catapult that will launch a marble to a given distance (between 2-3m). I have successfully made one out of wood, using a bungee cord to snap the arm back after being pulled on. My question is how do I calibrate this properly? Our teacher said we need...
  40. C

    How Fast Were the Catapulted Boulders Initially?

    Homework Statement A knight sits on a castle wall during a siege. To while away the time, he notes that boulders catapulted from below land on the top of his wall with a vertical velocity of 9.2 m/s. If he is 40 m above the catapult, what is the initial velocity of the boulders? The...
  41. A

    Catapult vertical displacement problem

    Homework Statement A catapult fires at an angle of 40.02 and has an initial velocity of 5.463. Find the vertical displacement at t=.38 seconds. I know the following from the problem and logic vo=5.463 t=.3824 g=9.8 angle=40.02 I calcuated the following voy=vosin40.02 voy=3.5133 Homework...
  42. A

    Catapult Physics for Game Programming

    hello I am a game programmer..and working on a game which has a player attached to the catapult arm. now when the arm is released the player gets thrown in the air.. while in air..the air resistance could make the player rotate left or right... and then glides and lands on the ground. i...
  43. T

    How To Calculate Catapult Trajectory

    I have an assignment where I have to build a catapult that is able to launch a bean bag any distance between 8-12 metres. My teacher will give me a random distance on the day it's due, and I have to be able to adjust the catapult in order for it to launch that distance. I'm having a bit of a...
  44. T

    Calculating Projectile Motion for a Catapult with Limited Data

    Hi Guys hope u r feeling good i just finished my catapult project and the problem is that i have only two given and the problem is that i have only two given values the \Delta T = 1.1 sec.\Delta_{d}x=2.2 m , and the angle is 70' degrees. and nothing else. http://tinypic.com/r/2ylqpux/7 i...
  45. Y

    Angular velocity and acceleration for catapult arm

    Homework Statement This isn't a homework problem, but I'm trying to do the calculations for a catapult I built to see if its actual performance matches the theoretical performance. I'm stuck trying to map the trajectory of the projectile. Here is the picture for reference...
  46. M

    Solving Catapult Problem: Launch Speed, Time in Air, and Impact Speed

    Homework Statement Catapults date from thousands of years ago, and were used historically to launch everything from stones to horses. During a battle in what is now Bavaria, inventive artillerymen from the united German clans launched giant spaetzle from their catapults toward a Roman...
  47. H

    Catapult final (impact) velocity

    Homework Statement I'm doing a catapult project and I have to calculate a few pieces of information. The initial velocity of the release (horizontal and vertical components) , the time of the highest point, and velocity of impact of the object. I know how to do all of these except find...
  48. L

    Energy efficiency of torsion Catapult

    Homework Statement How would you find the energy efficiency of a torsion catapult ? (one i built for project) I have the Force at which I am pulling the arm. F = 20N also the angle from origin to the point of release ( or when the ball leaves the arm) Theta = 50 degrees...